#ifndef SETTING_H_62B23520_7C8E_11DE_8A39_0800200C9A66
#define SETTING_H_62B23520_7C8E_11DE_8A39_0800200C9A66

#if defined(_MSC_VER) ||                                            \
    (defined(__GNUC__) && (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || \
     (__GNUC__ >= 4)) // GCC supports "pragma once" correctly since 3.4
#pragma once
#endif

#include "yaml-cpp/noexcept.h"
#include <memory>
#include <utility>
#include <vector>

namespace YAML {

class SettingChangeBase {
public:
    virtual ~SettingChangeBase() = default;
    virtual void pop() = 0;
};

template <typename T>
class Setting {
public:
    Setting() : m_value() {}
    Setting(const T& value) : m_value() { set(value); }

    const T get() const { return m_value; }
    std::unique_ptr<SettingChangeBase> set(const T& value);
    void restore(const Setting<T>& oldSetting) { m_value = oldSetting.get(); }

private:
    T m_value;
};

template <typename T>
class SettingChange : public SettingChangeBase {
public:
    SettingChange(Setting<T>* pSetting)
        : m_pCurSetting(pSetting),
          m_oldSetting(*pSetting) // copy old setting to save its state
    {}
    SettingChange(const SettingChange&) = delete;
    SettingChange(SettingChange&&) = delete;
    SettingChange& operator=(const SettingChange&) = delete;
    SettingChange& operator=(SettingChange&&) = delete;

    void pop() override { m_pCurSetting->restore(m_oldSetting); }

private:
    Setting<T>* m_pCurSetting;
    Setting<T> m_oldSetting;
};

template <typename T>
inline std::unique_ptr<SettingChangeBase> Setting<T>::set(const T& value) {
    std::unique_ptr<SettingChangeBase> pChange(new SettingChange<T>(this));
    m_value = value;
    return pChange;
}

class SettingChanges {
public:
    SettingChanges() : m_settingChanges{} {}
    SettingChanges(const SettingChanges&) = delete;
    SettingChanges(SettingChanges&&) YAML_CPP_NOEXCEPT = default;
    SettingChanges& operator=(const SettingChanges&) = delete;
    SettingChanges& operator=(SettingChanges&& rhs) YAML_CPP_NOEXCEPT {
        if (this == &rhs)
            return *this;

        clear();
        std::swap(m_settingChanges, rhs.m_settingChanges);

        return *this;
    }
    ~SettingChanges() { clear(); }

    void clear() YAML_CPP_NOEXCEPT {
        restore();
        m_settingChanges.clear();
    }

    void restore() YAML_CPP_NOEXCEPT {
        for (const auto& setting : m_settingChanges)
            setting->pop();
    }

    void push(std::unique_ptr<SettingChangeBase> pSettingChange) {
        m_settingChanges.push_back(std::move(pSettingChange));
    }

private:
    using setting_changes = std::vector<std::unique_ptr<SettingChangeBase>>;
    setting_changes m_settingChanges;
};
} // namespace YAML

#endif // SETTING_H_62B23520_7C8E_11DE_8A39_0800200C9A66
